Merge pull request #140 from build-cpp/improved-conditions

Allow arbitrary CMake expressions as conditions

docs/cmake-toml.md

@@ -67,15 +67,17 @@ _Note_: It is generally discouraged to disable the `C` language, unless you are
 
 ## Conditions
 
-You can specify your own conditions and use them in any `condition` field:
+You can specify your own named conditions and use them in any `condition` field:
 
 ```toml
 [conditions]
-arch64 = "CMAKE_SIZEOF_VOID_P EQUAL 8"
+ptr64 = "CMAKE_SIZEOF_VOID_P EQUAL 8"
-arch32 = "CMAKE_SIZEOF_VOID_P EQUAL 4"
+ptr32 = "CMAKE_SIZEOF_VOID_P EQUAL 4"
 ```
 
-This will make the `arch64` and `arch32` conditions available with their respective CMake expressions.
+This will make the `ptr64` and `ptr32` conditions available with their respective CMake expressions.
+
+**Note**: condition names can only contain lower-case alphanumeric characters (`[0-9a-z]`) and dashes (`-`).
 
 You can also prefix most keys with `condition.` to represent a conditional:
 
@@ -83,9 +85,11 @@ You can also prefix most keys with `condition.` to represent a conditional:
 [target]
 type = "executable"
 sources = ["src/main.cpp"]
-windows.sources = ["src/windows_specific.cpp"]
+ptr64.sources = ["src/ptr64_only.cpp"]
 ```
 
+Instead of a named condition you can also specify a [CMake expression](https://cmake.org/cmake/help/latest/command/if.html#condition-syntax) in quotes. Instances of `$<name>` are replaced with the corresponding condition. For example: `"CONDITIONS_BUILD_TESTS AND $<linux>"` becomes `CONDITIONS_BUILD_TESTS AND (CMAKE_SYSTEM_NAME MATCHES "Linux")` in the final `CMakeLists.txt` file.
+
 ### Predefined conditions
 
 The following conditions are predefined (you can override them if you desire):
@@ -131,7 +135,7 @@ MYPROJECT_SPECIAL_OPTION = { value = true, help = "Docstring for this option." }
 MYPROJECT_BUILD_EXAMPLES = "root"
 ```
 
-Options correspond to [CMake cache variables](https://cmake.org/cmake/help/book/mastering-cmake/chapter/CMake%20Cache.html) that can be used to customize your project at configure-time. You can configure with `cmake -DMYPROJECT_BUILD_TESTS=ON` to enable the option. Every option automatically gets a corresponding [condition](#conditions).
+Options correspond to [CMake cache variables](https://cmake.org/cmake/help/book/mastering-cmake/chapter/CMake%20Cache.html) that can be used to customize your project at configure-time. You can configure with `cmake -DMYPROJECT_BUILD_TESTS=ON` to enable the option. Every option automatically gets a corresponding [condition](#conditions). Additionally, a normalized condition is created based on the `[project].name` (i.e. `MYPROJECT_BUILD_TESTS` becomes `build-tests`).
 
 The special value `root` can be used to set the option to `true` if the project is compiled as the root project (it will be `false` if someone is including your project via `[fetch-content]` or `[subdir]`).
 
@@ -149,8 +153,8 @@ Variables emit a [`set`](https://cmake.org/cmake/help/latest/command/set.html) a
 
 ```toml
 [vcpkg]
-version = "2021.05.12"
+version = "2024.03.25"
-url = "https://github.com/microsoft/vcpkg/archive/refs/tags/2021.05.12.tar.gz"
+url = "https://github.com/microsoft/vcpkg/archive/refs/tags/2024.03.25.tar.gz"
 packages = ["fmt", "zlib"]
 ```
 

include/project_parser.hpp

@@ -208,6 +208,7 @@ struct Project {
     Project(const Project *parent, const std::string &path, bool build);
     const Project *root() const;
     bool cmake_minimum_version(int major, int minor) const;
+    static bool is_condition_name(const std::string &name);
 };
 
 bool is_root_path(const std::string &path);

src/cmake_generator.cpp

@@ -514,15 +514,13 @@ struct Generator {
         if (!value.empty()) {
             for (const auto &itr : value) {
                 const auto &condition = itr.first;
-                if (!condition.empty()) {
+                auto endif = if_condition(condition);
-                    cmd("if", condition)(RawArg(project.conditions.at(condition)));
-                }
 
                 if (!itr.second.empty()) {
                     fn(condition, itr.second);
                 }
 
-                if (!condition.empty()) {
+                if (endif) {
                     cmd("endif")().endl();
                 } else if (!itr.second.empty()) {
                     endl();
@@ -538,6 +536,68 @@ struct Generator {
     void conditional_cmake(const parser::Condition<std::string> &cmake) {
         handle_condition(cmake, [this](const std::string &, const std::string &cmake) { inject_cmake(cmake); });
     }
+
+    bool if_condition(const std::string &condition) {
+        if (condition.empty()) {
+            return false;
+        }
+        auto found = project.conditions.find(condition);
+        if (found == project.conditions.end()) {
+            if (cmkr::parser::Project::is_condition_name(condition)) {
+                // NOTE: this should have been caught by the parser already
+                throw std::runtime_error("Condition '" + condition + "' is not defined");
+            }
+            cmd("if", "NOTE: unnamed condition")(RawArg(cmake_condition(condition)));
+        } else {
+            cmd("if", condition)(RawArg(found->second));
+        }
+        return true;
+    }
+
+  private:
+    std::string cmake_condition(const std::string &condition) {
+        // HACK: this replaces '$<name>' with the value of the 'name' condition. We can safely
+        // reuse the generator expression syntax, because it is not valid in CMake conditions.
+        // TODO: properly handle quoted arguments (using a simple state machine):
+        // https://cmake.org/cmake/help/latest/manual/cmake-language.7.html#quoted-argument
+        std::string result = "";
+        bool in_replacement = false;
+        std::string temp;
+        for (size_t i = 0; i < condition.length(); i++) {
+            if (in_replacement) {
+                if (condition[i] == '>') {
+                    in_replacement = false;
+                    if (temp.empty()) {
+                        throw std::runtime_error("Empty replacement in condition '" + condition + "'");
+                    }
+                    auto found = project.conditions.find(temp);
+                    if (found == project.conditions.end()) {
+                        throw std::runtime_error("Unknown condition '" + temp + "' in replacement");
+                    }
+                    auto has_space = found->second.find(' ') != std::string::npos;
+                    if (has_space) {
+                        result += '(';
+                    }
+                    result += found->second;
+                    if (has_space) {
+                        result += ')';
+                    }
+                    temp.clear();
+                } else {
+                    temp += condition[i];
+                }
+            } else if (condition[i] == '$' && i + 1 < condition.length() && condition[i + 1] == '<') {
+                i++;
+                in_replacement = true;
+            } else {
+                result += condition[i];
+            }
+        }
+        if (!temp.empty()) {
+            throw std::runtime_error("Unterminated replacement in condition '" + condition + "'");
+        }
+        return result;
+    }
 };
 
 struct ConditionScope {
@@ -545,10 +605,7 @@ struct ConditionScope {
     bool endif = false;
 
     ConditionScope(Generator &gen, const std::string &condition) : gen(gen) {
-        if (!condition.empty()) {
+        endif = gen.if_condition(condition);
-            gen.cmd("if", condition)(RawArg(gen.project.conditions.at(condition)));
-            endif = true;
-        }
     }
 
     ConditionScope(const ConditionScope &) = delete;

src/project_parser.cpp

@@ -140,7 +140,7 @@ class TomlChecker {
         for (const auto &itr : m_v.as_table()) {
             const auto &ky = itr.first;
             if (m_conditionVisited.contains(ky)) {
-                if (!conditions.contains(ky)) {
+                if (!conditions.contains(ky) && Project::is_condition_name(ky)) {
                     throw_key_error("Unknown condition '" + ky + "'", ky, itr.second);
                 }
 
@@ -160,7 +160,7 @@ class TomlChecker {
                 throw_key_error("Unknown key '" + ky + "'", ky, itr.second);
             } else if (ky == "condition") {
                 std::string condition = itr.second.as_string();
-                if (!conditions.contains(condition)) {
+                if (!conditions.contains(condition) && Project::is_condition_name(condition)) {
                     throw_key_error("Unknown condition '" + condition + "'", condition, itr.second);
                 }
             }
@@ -282,6 +282,9 @@ Project::Project(const Project *parent, const std::string &path, bool build) : p
     if (checker.contains("conditions")) {
         auto conds = toml::find<decltype(conditions)>(toml, "conditions");
         for (const auto &cond : conds) {
+            if (!is_condition_name(cond.first)) {
+                throw_key_error("Invalid condition name '" + cond.first + "'", cond.first, toml::find(toml::find(toml, "conditions"), cond.first));
+            }
             conditions[cond.first] = cond.second;
         }
     }
@@ -372,6 +375,24 @@ Project::Project(const Project *parent, const std::string &path, bool build) : p
     }
 
     if (checker.contains("options")) {
+        auto normalize = [](const std::string &name) {
+            std::string normalized;
+            for (char ch : name) {
+                if (ch == '_') {
+                    normalized += '-';
+                } else if (ch >= 'A' && ch <= 'Z') {
+                    normalized += std::tolower(ch);
+                } else if (ch == '-' || (ch >= '0' && ch <= '9') || (ch >= 'a' && ch <= 'z')) {
+                    normalized += ch;
+                } else {
+                    // Ignore all other characters
+                }
+            }
+            return normalized;
+        };
+        auto nproject_prefix = normalize(project_name);
+        nproject_prefix += '-';
+
         using opts_map = tsl::ordered_map<std::string, TomlBasicValue>;
         const auto &opts = toml::find<opts_map>(toml, "options");
         for (const auto &itr : opts) {
@@ -409,7 +430,18 @@ Project::Project(const Project *parent, const std::string &path, bool build) : p
                 throw_key_error(toml::concat_to_string("Unsupported value type: ", itr.second.type()), itr.first, itr.second);
             }
             options.push_back(o);
-            conditions.emplace(o.name, o.name);
+
+            // Add an implicit condition for the option
+            auto ncondition = normalize(o.name);
+            if (ncondition.find(nproject_prefix) == 0) {
+                ncondition = ncondition.substr(nproject_prefix.size());
+            }
+            if (!ncondition.empty()) {
+                if (conditions.contains(ncondition)) {
+                    print_key_warning("Option '" + o.name + "' would create a condition '" + ncondition + "' that already exists", o.name, value);
+                }
+                conditions.emplace(ncondition, o.name);
+            }
         }
     }
 
@@ -639,28 +671,28 @@ Project::Project(const Project *parent, const std::string &path, bool build) : p
 
         Condition<std::string> msvc_runtime;
         t.optional("msvc-runtime", msvc_runtime);
-        for (const auto &condItr : msvc_runtime) {
+        for (const auto &cond_itr : msvc_runtime) {
-            switch (parse_msvcRuntimeType(condItr.second)) {
+            switch (parse_msvcRuntimeType(cond_itr.second)) {
             case msvc_dynamic:
-                target.properties[condItr.first]["MSVC_RUNTIME_LIBRARY"] = "MultiThreaded$<$<CONFIG:Debug>:Debug>DLL";
+                target.properties[cond_itr.first]["MSVC_RUNTIME_LIBRARY"] = "MultiThreaded$<$<CONFIG:Debug>:Debug>DLL";
                 break;
             case msvc_static:
-                target.properties[condItr.first]["MSVC_RUNTIME_LIBRARY"] = "MultiThreaded$<$<CONFIG:Debug>:Debug>";
+                target.properties[cond_itr.first]["MSVC_RUNTIME_LIBRARY"] = "MultiThreaded$<$<CONFIG:Debug>:Debug>";
                 break;
             default: {
-                std::string error = "Unknown runtime '" + condItr.second + "'\n";
+                std::string error = "Unknown runtime '" + cond_itr.second + "'\n";
                 error += "Available types:\n";
                 for (std::string type_name : msvcRuntimeTypeNames) {
                     error += "  - " + type_name + "\n";
                 }
                 error.pop_back(); // Remove last newline
                 const TomlBasicValue *report;
-                if (condItr.first.empty()) {
+                if (cond_itr.first.empty()) {
                     report = &t.find("msvc-runtime");
                 } else {
-                    report = &t.find(condItr.first).as_table().find("msvc-runtime").value();
+                    report = &t.find(cond_itr.first).as_table().find("msvc-runtime").value();
                 }
-                throw_key_error(error, condItr.second, *report);
+                throw_key_error(error, cond_itr.second, *report);
             }
             }
         }
@@ -833,6 +865,16 @@ bool Project::cmake_minimum_version(int major, int minor) const {
     return std::tie(root_major, root_minor) >= std::tie(major, minor);
 }
 
+bool Project::is_condition_name(const std::string &name) {
+    auto is_named_condition = true;
+    for (auto ch : name) {
+        if (!(ch == '-' || (ch >= '0' && ch <= '9') || (ch >= 'a' && ch <= 'z'))) {
+            return false;
+        }
+    }
+    return true;
+}
+
 bool is_root_path(const std::string &path) {
     const auto toml_path = fs::path(path) / "cmake.toml";
     if (!fs::exists(toml_path)) {

tests/conditions/cmake.toml

@@ -2,6 +2,9 @@
 name = "conditions"
 cmake-after = "set(CUSTOM ON)"
 
+[options]
+CONDITIONS_BUILD_TESTS = "root"
+
 [conditions]
 custom = "CUSTOM"
 
@@ -15,6 +18,8 @@ macos.cmake-after = "message(STATUS macos-after)"
 linux.cmake-after = "message(STATUS linux-after)"
 unix.cmake-after = "message(STATUS unix-after)"
 custom.cmake-after = "message(STATUS custom-after)"
+build-tests.cmake-after = "message(STATUS build-tests)"
+"CONDITIONS_BUILD_TESTS AND $<linux>".cmake-after = "message(STATUS linux-tests)"
 
 [target.example.properties]
 AUTOMOC = false